On the contribution of thermal excitation to the total 630.0 nm emissions in the northern cusp ionosphere

Direct impact excitation by precipitating electrons is believed to be the main source of 630.0 nm emissions in the cusp ionosphere. However, this paper investigates a different source, 630.0 emissions caused by thermally excited atomic oxygen O$(^{1}$D) when high electron temperature prevail in the cusp. On 22 January 2012 and 14 January 2013, the European Incoherent Scatter Scientific Association (EISCAT) radar on Svalbard measured electron temperature enhancements exceeding 3000 K near magnetic noon in the cusp ionosphere over Svalbard. The electron temperature enhancements corresponded to electron density enhancements exceeding $10^{11}$m$^{-3}$ accompanied by intense 630.0 nm emissions in a field of view common to both the EISCAT Svalbard radar and a meridian scanning photometer. This offered an excellent opportunity to investigate the role of thermally excited O$(^{1}$D) 630.0 nm emissions in the cusp ionosphere. The thermal component was derived from the EISCAT Radar measurements and compared with optical data. For both events the calculated thermal component had a correlation coefficient greater than 0.8 to the total observed 630.0 nm intensity which contains both thermal and particle impact components. Despite fairly constant solar wind, the calculated thermal component intensity fluctuated possibly due to dayside transients in the aurora

Diabetic gastroenteropathy examined with wireless motility capsule

Background Diabetic gastroenteropathy may affect all parts of the gastrointestinal tract. Despite being prevalent, knowledge is limited and treatment often generalised and unsatisfactory. To deliver personalised treatment, there is a need for improved diagnostics. In this study, we have investigated the role of the wireless motility capsule in the evaluation of gastroparesis, diarrhoea, and constipation, the three main manifestations of diabetic gastroenteropathy. Methods We included 72 diabetes patients (49 women; 59 type 1 diabetes) with gastrointestinal symptoms. They were investigated with blood, urinary and faecal samples, questionnaires, autonomic function tests, and gastrointestinal motility and function tests, including wireless motility capsule and gastric emptying scintigraphy. During fasting and examinations, patients were kept on intravenous glucose-insulin infusion. We also investigated 26 healthy participants using wireless motility capsule. Results In paper 1, we found that the wireless motility capsule had high diagnostic accuracy compared to scintigraphy for determining gastric emptying. In paper 2, we found that patients with diarrhoea had increased gastric emptying time, reduced colonic transit time, and altered gastrointestinal pH levels. In paper 3, we found no difference in transit times when comparing diabetes patients with and without constipation, but both diabetes groups had slower whole gut transit than healthy controls. Conclusions The wireless motility capsule may have a role in the investigation of patients with suspected diabetic gastroenteropathy. It has high diagnostic accuracy for measuring gastric emptying and may identify clinically relevant alterations in gastrointestinal transit and pH levels. We recommend further validation of the capsule’s pH and contractility measurements before they are used in routine examinations.Doktorgradsavhandlin

Compaction dynamics in ductile granular media

Ductile compaction is common in many natural systems, but the temporal evolution of such systems is rarely studied. We observe surprising oscillations in the weight measured at the bottom of a self-compacting ensemble of ductile grains. The oscillations develop during the first ten hours of the experiment, and usually persist through the length of an experiment (one week). The weight oscillations are connected to the grain--wall contacts, and are directly correlated with the observed strain evolution and the dynamics of grain--wall contacts during the compaction. Here, we present the experimental results and characteristic time constants of the system, and discuss possible reasons for the measured weight oscillations.Comment: 11 pages, 14 figure

A New, Highly Conductive, Lithium Salt/Nonionic Surfactant, Lyotropic Liquid-Crystalline Mesophase and Its Application

Cataloged from PDF version of article.Salty water! Lithium salts (LiCl, LiNO3, and LiClO4) at very high concentrations in water form lyotropic liquid crystalline (LLC) mesophases with a nonionic surfactant (10-lauryl ether) and display high ionic conductivities (10−2–10−4 S cm−1) over a broad temperature range (−10 to 80 °C) with excellent behavior as gel electrolytes in electrochemical applications

Water Chemistry in the Confluence Zone Downstream a Limestone Treated Lake and an Acid Tributary: Principal Component Analyses Including Warm and Cold Winters and an Episode High in Sea-Salts

Extensive limestone treatment of lakes and watercourses has been carried out especially in Norway and Sweden to counteract effects of acidification. Lakes have been the most commonly treated part of the water systems. However, treatment of lakes upstream acid tributaries may introduce downstream toxic mixing zones for fish. To sort this out the outlet of a treated lake, a downstream acid tributary and two sites in the confluence zone were intensely monitored during a period of 28 months. The data accumulated come from a period (from February 1992) where significant climatic variations took place that provide a basis for studying intercorrelations between water chemistry and climatic change. The first two winters were warmer than normal and the catchments were hardly covered with snow and the lake was ice-covered only for a few days. The last winter was colder than normal, nival and the lake was ice-covered from December to April. During the second winter a low pressure over the north Atlantic gave strong south-westerly winds and large amounts of precipitation loaded with sea-salts. The principal component analysis (PCA) separates both the outlet and the tributary data into two groups while the data from the confluence zone are separated into three. Significant different water chemistry was observed in the outlet during the ice-covered period while effects of the sea-salt event splits the data from the tributary into two groups. The water chemistry in the confluence zone reflects both the ice-covered period, the sea-salt event and besides the more general situation. The PCA analysis indicates that the changing weather conditions mainly influenced on the water quality in the tributary. The water quality in the confluence zone was generally a conservative mixture of the outlet and the tributary waters except for alkalinity, H+ and inorganic aluminium (Ali). Generally, hydrolysing Ali in the confluence rendered the water quality highly toxic to fish. The potential toxicity increased during the sea-salt event and during the ice-covered period of the lake due to increased concentrations of Ali both in the outlet and the tributary waters. The results indicate that this may be a general problem in confluence zones downstream limestone treated lakes and acid tributaries

The effect of anions of transition metal salts on the structure of modified mesostructured silica films and monoliths

Cataloged from PDF version of article.The structure of the preformed LC mesophase of water:transition metal salt ([M(H2O)6]X2):acid (HX):oligo(ethylene oxide) (or Pluronics):tetramethylorthosilicate (TMOS) mixture during hydrolysis and partial polymerization of the silica source is maintained upon further polymerization and condensation of the silica species in the solid state. The liquid mixture in early stage of the silica polymerization could be casted or dip coated to a surface of a glass or silicon wafer to produce mesostructured silica monoliths and films, respectively. The silica species and ions (metal ions and anions) influence the structure of the LC mesophases (as a result, the structure of silica) and the hydrophilic and hydrophobic balance in the reaction media. The silica structure can be changed from hexagonal to cubic by increasing, for example, the nitrate salt concentration in the nitrate salt systems. A similar transformation takes place in the presence of very low perchlorate salt concentration. The salt concentration in the mesostructured silica can be increased up to 1.1/1.0 salt/SiO2 w/w ratio, in mesostructured silica materials by maintaining its lamella structure in P123 and cubic in the CnEOm systems. However, the materials obtained from the P123 systems undergo transformation from lamella to 2D hexagonal upon calcinations. The method developed in this work can be used to modify the internal surface of the pores with various transition metal ions and metal oxides that may find application in catalysis. © 2006 Elsevier Inc. All rights reserved

A Study of Mass Transfer Kinetics of Carbon Dioxide in (Monoethanolamine + Water) by Stirred Cell

AbstractThe gas phase resistance in a stirred cell was investigated to understand and avoid its influence on the measurement of the reaction kinetics. To validate the influence of gas phase resistance and the experimental conditions of pseudo first order reaction for Monoethanolamine (MEA) + CO2 system, low CO2 partial pressure under various inert gas pressure were employed for CO2 the absorption into 0.5, 1, 3 and 3.6M MEA solutions with H2O and ethyleneglycol as solvents, respectively. The absorption was investigated with the stirred cell based on a fall-in-pressure technique

The effect of cationic surfactant and some organic/inorganic additives on the morphology of mesostructured silica templated by pluronics

Cataloged from PDF version of article.Tri-block copolymers (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), represented as EOxPOyEOx), pluronics (F127=EO106PO70EO106, P65=EO20PO30EO20, P85=EO27PO39EO27, P103= EO17PO55EO17, and P123 = EO20PO70EO20) and cationic surfactants (cethyltrimethylammonium bromide (CTAB)), two surfactant systems, form complex micelles that self-assemble into mesostructured particles with distinct morphology depending on the pluronic type, the concentration of the cationic surfactant and the organic-inorganic ingredients in a siliceous reaction media under acidic conditions. The CTAB-P65 and CTAB-P85 systems form spheres, CTAB-P103 and CTAB-P123 systems form wormlike particles, and CTAB-F127 system form single crystals of mesostructured silica particles under very similar conditions. However addition of various salts (such as KCI and NaNO3) into a CTAB-P103 or CTAB-P123 solution system and cyclohexane and KCI into a CTAB-P85 solution system produces the mesostructured silica spheres and wormlike particles, respectively. By controlling the hydrophilic-hydrophobic character of the pluronics, core-corona interface, by means of additives, such as small organic molecules or salts, one could obtain the desired morphology that is dictated by the shape of the micelles of the pluronic-cationic surfactant complex. The effects of the additives and the formation mechanism of those morphologies have been discussed using spectroscopy (FT-IR and Raman), diffraction (XRD) and microscopy (POM and SEM) data. (c) 2008 Elsevier Inc. All rights reserved